Truss arm



FIG. 1 is a front isometric view of the truss arm, showing the new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a side elevation view thereof;

FIG. 5 is another side elevation view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken lines in the drawings depict parts of the truss arm that form no part of the claimed design. 

CLAIM The ornamental design for a truss arm, as shown and described. 